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Post by luis on Sept 18, 2021 14:29:13 GMT -8
If the brass nut does not come off easily, don't put any pressure one it. It is brass and will break. Instead, remove the entire LP assembly, hold the LP seat with pliers and turn the nut IN slightly, rocking it back and forth until you loosen the staking. If you do break it, all is not lost, reproductions exist. There is even a reproduction that is a bit longer with a slot for a tiny screwdriver to hold the poppet from turning. That allows you to use a Nylock nut to keep it from rotating without the need of nail-polish or other goop.
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Post by SeaRat on Sept 18, 2021 15:41:23 GMT -8
Luis, I understand your thoughts about what the human body can withstand. As a former USAF Pararescueman, and Master Parachutist, we got a lot of practice in that. I have also jumped out of helicopters, and with the pilot at 20 feet, that can be quite an impact. Having a working knowledge of fall arrest systems, and having put them into proctice in my 30+ year work in professional safety and industrial hygiene, these are important concepts. Now concerning the DA Aquamaster and the twist on those pivots ("Support Lock," left and right), my U.S. Navy Diving Manual 1970 shows in the 6.7 ASSEMBLY AND TEST PROCEDURE--DEMAND REGULATOR," that step reads, "(e) deleted." I think this "e" was the step for twisting that support lock. What I described above about the twist is what was told to us in the U.S. Navy School for Underwater Swimmers in 1967 by the instructors there. I'm sure that you are correct about the demand lever not being able to be displaced, but it was in the minds of those who wrote the initial instructions, otherwise it would not have happened. Parascuba Jump-Okinawa-1 by John Ratliff, on Flickr Thanks for the information. John
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Post by luis on Sept 18, 2021 17:08:04 GMT -8
Luis, I understand your thoughts about what the human body can withstand. As a former USAF Pararescueman, and Master Parachutist, we got a lot of practice in that. I have also jumped out of helicopters, and with the pilot at 20 feet, that can be quite an impact. Having a working knowledge of fall arrest systems, and having put them into proctice in my 30+ year work in professional safety and industrial hygiene, these are important concepts. Now concerning the DA Aquamaster and the twist on those pivots ("Support Lock," left and right), my U.S. Navy Diving Manual 1970 shows in the 6.7 ASSEMBLY AND TEST PROCEDURE--DEMAND REGULATOR," that step reads, "(e) deleted." I think this "e" was the step for twisting that support lock. What I described above about the twist is what was told to us in the U.S. Navy School for Underwater Swimmers in 1967 by the instructors there. I'm sure that you are correct about the demand lever not being able to be displaced, but it was in the minds of those who wrote the initial instructions, otherwise it would not have happened.
Thanks for the information. John I have no doubt that someone thought that. I have run into similar situations many times. In my regular job, it is amazing how many times I have to chase down why are we doing something in some particular way. I love the answer: "well, that is the way we have always done it…" So what? Does that mean it’s got to be right? Just because it worked with sailing ships… it may not the best way forward… I have run into dead ends a number of times where we can’t find the history or an explanation, other than somebody thought it was a good idea… and at the time, with the available information it might have been. Thanks
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Post by Jim Perdway on Sept 18, 2021 18:32:04 GMT -8
Thank you everyone for your help today. I really appreciate the personal tips and cautions before jumping right into a manual and starting. It’s not clear to me yet the meaning of the staked thread but perhaps it will be clear when I get home and look at it closer. I’m excited to get this rebuild underway
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Post by vance on Sept 18, 2021 19:06:04 GMT -8
Staking a nut simply means to take a sharp punch and tap the intersection of the nut and screw (in this case a poppet stem) to lock the nut into place. Here's a photo showing a staked IP adjuster. Instead of staking, we generally use a drop of nail polish. Color is up to you. Here's your RAM photo detail showing the staking and the twisted retaining "ear".
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Post by Jim Perdway on Sept 18, 2021 19:28:29 GMT -8
Oh I see, thanks for clarification Phil
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Post by luis on Sept 18, 2021 20:53:19 GMT -8
Staking a nut simply means to take a sharp punch and tap the intersection of the nut and screw (in this case a poppet stem) to lock the nut into place. Here's a photo showing a staked IP adjuster. Instead of staking, we generally use a drop of nail polish. Color is up to you. I prefer bright red so that I can see it clearly that it is done. If you take a close look at your picture, you can see the stake between the threads at the top of the nut and the poppet threads
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Post by herman on Sept 19, 2021 3:44:39 GMT -8
I use what ever color the wife no longer thinks is "pretty". Apparently, the color goes bad after a while, when new it's pretty but after a few months it goes ugly..still looks the same to me. The IP adjustment does not need to be sealed, it will not move. Before proceeding with the disassembly I highly suggest you search around on this board, VDH and Scubaboard for tips and tricks. Myself and others have posted a number of useful bits of rebuild information over the years on these boards and by all means, ASK QUESTIONS, there is a lot of rebuild experience around. One more bit of advice....a warning really, DO NOT breath off of the supply horn directly, always have a hose loop installed. These regs have a very strong venturi and when, not IF but when, you set if off it will flow violently. If you have your mouth around the horn, you can do serious damage to your lungs.
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Post by vance on Sept 19, 2021 7:51:50 GMT -8
You can unscrew the retaining ears with the lever in place. Slip the lever off the poppet. Unscrew the second stage body to remove it from the valve body, poppet and all.
Then grab the poppet from the opening at the bottom with a pair of needle nose pliers and turn the nut clockwise to break the staking. Turn the nut back and forth until you can get it to unscrew with reasonable force. If you break the stem, replace it with the one with a screwdriver slot that Luis recommended.
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Post by snark3 on Sept 19, 2021 8:36:00 GMT -8
In many applications other than regulators I've used "pal nuts" or double nuts. When two nuts are tightened together they don't move. Is there a reason this method wasn't or can't be used?
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Post by luis on Sept 19, 2021 10:40:23 GMT -8
In many applications other than regulators I've used "pal nuts" or double nuts. When two nuts are tightened together they don't move. Is there a reason this method wasn't or can't be used? Great question. I tried that a while back and it kind of worked, but not very well. In some cases it didn't work at all. The original poppet stem is kind of short. You have to use two thin nuts. It was also hard to grab the lower nut, because you have to use thin nuts and there is some interference with the lever, when you are also grabbing the top nut. If you look at the zoomed in picture Vance posted you can see that there only about one thread available for a second nut. A second nut would be unreliable in that situation. The newer longer replacement poppets could be double nutted, but they also have a screwdriver slot, so they are best used with a Nylock nut. And, there is always the alternative of upgrading to an HPR second stage. I don't want it to sound like I am biased, but the response I received from everyone that has upgraded is outstanding. It really improves performance and ease of future service without being a permanent change and from the outside no one can tell about the upgrade. BTW, I get absolutely no benefit from the sale an HPR. I have no financial involvement with the fabrication or sale. But I am happy that people like it... It is not the original configuration so it is not for everybody...
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Post by luis on Sept 19, 2021 12:16:11 GMT -8
You can unscrew the retaining ears with the lever in place. Slip the lever off the poppet. Unscrew the second stage body to remove it from the valve body, poppet and all. Then grab the poppet from the opening at the bottom with a pair of needle nose pliers and turn the nut clockwise to break the staking. Turn the nut back and forth until you can get it to unscrew with reasonable force. If you break the stem, replace it with the one with a screwdriver slot that Luis recommended. That was my preferred way to take it apart. And I figured out a way to reverse the process to put it back together if I liked the nut location and didn't want to disturb the seal (nail polish). It helps to push the lever down to lift the poppet and place a spacer under the exposed side of the nut and washer. I used another nut or washer as the spacer (or an old HP seat with a washer). Now the spring is compressed and it is a lot easier to remove the lever when you loosen the two supporting screws.
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Post by Jim Perdway on Sept 20, 2021 6:25:41 GMT -8
For this particular reg, I’d like to maximize performance and serviceability while retaining original exterior appearance (with the exception of those damn box clips haha). I already got the eliminator so I might as well keep the mods coming and go with the HPR. For the sake of learning and experience, would you recommend I rebuild first with the original 2nd?
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Post by james1979 on Sept 20, 2021 6:43:07 GMT -8
For this particular reg, I’d like to maximize performance and serviceability while retaining original exterior appearance (with the exception of those damn box clips haha). I already got the eliminator so I might as well keep the mods coming and go with the HPR. For the sake of learning and experience, would you recommend I rebuild first with the original 2nd? I personally wouldn't rebuild with the original, but would do the careful disassembly and cleaning. In my limited experience, the assembly is pretty straight forward and easy.... it's getting it apart without breaking the stem that requires some care. Then you can put the second stage away, assembled and clean ready to go as a spare... you know, for the next project! lol Best, James
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Post by Jim Perdway on Sept 20, 2021 16:16:07 GMT -8
I'm putting together my parts order for the project on VDH and have a couple questions. He recommends when replacing the hp seat to get a new teflon backup washer if the reg uses one. I wanted to see if mine likely uses one and if so, to clarify that the part I need is the "updated crown block backup washer" Also, it looks like I'll need to get a conshelf pin and trim it down to correct length. I worry about doing this accurately, so I'll cover postage and whatever additional labor cost if someone can trim it for me.
Thanks
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